This invention relates to the field of materials and processes for the absorption and removal of hydrocarbon contaminants from ground surfaces, water or the soil.
Hydrocarbons, especially oil, refined gasoline and the like, are intensely poisonous chemicals to most plant life, and, as a result, relatively low levels of hydrocarbon contamination are capable of sterilizing soil. Therefore, the extraction and removal of hydrocarbon contaminants and spills from the ground and from ground water in the soil has become a particularly important environmental objective.
Two basic products and processes exist for the alleviation of hydrocarbon or oil spills. The first are those products and processes which are used to absorb oil from ground spills. The most noted of these are the clay absorbents formed of various forms of calcined clay and/or zeolite mixtures sold as products under such trade names as "Speedi-Dri" and other similar names. Such products are also sold widely in the form of animal litters. All such products are generally characterized in that they are particulates with physical adsorption properties that are adapted to absorb and bind hydrocarbons in a disposable form. However, an absorbent becomes contaminated in turn by the hydrocarbon and, thus, still presents a major disposal problem.
A second technique in use is that of bacterial remediation of hydrocarbon spills. In these techniques, various specialized strains of bacteria have been developed which metabolize various hydrocarbons and gradually reduce them to carbon dioxide and water. Such remediation is the only process currently known which is capable of actually eliminating hydrocarbon contamination as opposed to merely absorbing it and removing it to a second location. However, such bacterial remediation requires that the bacteria and the hydrocarbon be brought into intimate contact under conditions in which the bacteria will act to metabolize the hydrocarbons. This requires extensive labor and effort to spread the bacteria on the soil and then to continually work and rework the contaminated area, turning and tilling the soil, until such time as the bacteria have been brought substantially into contact with all of the contaminated hydrocarbon particles. Further, this leaves a problem in that the bacteria may themselves be an undesirable or toxic contaminant in the soil, since the bacteria have been specially bred for the purposes of metabolizing and reducing hydrocarbons. Such bacteria may otherwise be an undesirable species for future use of the soil as a growing or plant support medium.